Yo-yo dieting among teens has negative long-term effects

Monday

Feb 27, 2012 at 12:01 AMFeb 27, 2012 at 1:58 AM

Body mass index, or BMI, is the number many teens should be paying attention to. But they are often obsessed with their own weight rather than whether they are healthy. Here's what parents should know.

Julie Kaiser

Remember when teaching the toddler not to hurl food at the family pet or enticing your grade-schooler to eat his peas made up your biggest meal-time issues?

If that toddler has grown into a teenager who experiments with a different diet plan every other week, your parenting focus probably needs to shift yet again.

Dr. Gregory Bennett, associate professor of pediatrics at Southern Illinois University School of Medicine in Springfield, Ill., says that while parents shouldn’t obsess over a child’s weight or body size, the body mass index (BMI) is an important indicator of overall health.

According to the Centers for Disease Control and Prevention, BMI is made up of a person’s height and weight to determine his or her “fatness.” BMI can be used to screen for weight categories that may lead to health problems.

“I think it’s probably worth it when they (children) have annual checkups to ask the doctor about their body mass index,” he said.

“Where does the BMI plot out? How does it compare to last year? Little changes in BMI can be an early clue for a doctor, and it’s a good thing to talk about every year, every visit.”

Last month, The Journal of Adolescent Health reported results from a 10-year study that indicates teenagers who engage in extended cycles of yo-yo dieting end up increasing their body mass index years later: “Specific weight control behaviors used during adolescence that predicted large increases in BMI at 10-year follow-up included skipping meals and reporting eating very little (females and males), use of food substitutes (males), and use of diet pills (females).”

The report’s authors went on to say: “It is crucial to find ways to steer young people away from these ineffective and potentially harmful weight control behaviors, and provide support for the adoption of healthful eating and physical activity behaviors that can be implemented on a long-term basis.”

Get moving

Avoiding the attraction of the latest quick diet fix is a challenge, not only for teenagers but for adults.

Bennett believes that instead of worrying about a child’s body size, parents should instead focus their children (and themselves) on three areas: adequate exercise, healthy food choices and drinking plenty of water.

“Everyone thinks their kids are active, but the truth is that most aren’t getting good quality exercise,” he says. “Children should definitely exercise on a daily basis — 20 to 60 minutes of true exercise.”

Bennett said most kids don’t get that amount of exercise daily, but they are capable of achieving it. He recommends involving friends or even parents because people tend to be more successful with exercise when they have someone to do it with.

How they look at it

Teen’s food choices alarm parents, however, especially when their child is experimenting with different diets or simply exhibiting unusual behavior at mealtime. Sometimes that behavior can lead to more serious issues, including eating disorders such as anorexia or bulimia.

Pat Scott is the student assistance coordinator for Glenwood High School in Chatham, Ill. She says parents should be alert when their children start eating only fruits or vegetables, push food away or become preoccupied with taking in only small portions.

“Another sign is when your kids aren’t spending time at family events where people will eat and celebrate,” she says. “Maybe they back out of those activities because they are becoming more obsessed with their weight.”

She adds that adolescence is a time when both boys and girls begin to pay extra attention to their bodies. It’s not just girls who struggle with self-esteem related to their body image, either. Boys can strive to emulate the body image of athletes or even other students who are lifting weights and working out.

“All kids probably have some distortion of their body image where what they see when they look in the mirror may not be what others see,” he says. “To an extent, that’s normal. When we become concerned is when that becomes out of control.”

For example, he says, some kids have such a distorted body image that it can cause them other problems in their social interactions, with their family and with their health.

“If you truly have a patient who believes they are fat when everyone else thinks they are too thin, that’s a problem,” Bennett said.

He also frowns on the idea of dieting in general.

“I don’t think I’ve ever talked with a child or adolescent where my recommendation was to go on a diet,” Bennett said. “It just doesn’t work. The recommendation I would always make for someone who is overweight or underweight would be a much more global approach to just being healthy. Make smart choices about what you eat, what you drink. Definitely begin a lifetime commitment to daily exercise.”

When you approach it from all those angles, he adds, you have a higher success rate to have and keep a healthy BMI.

Calculating BMI

The Centers for Disease Control and Prevention have an online body mass index calculator. Use it at http://tinyurl.com/b53foz

A BMI of between 18.5 to 24.9 is considered normal for an adult. Adults are overweight if their body mass index is between 25 and 29.9, and considered obese if the BMI is 30 or larger.

For teens and children, calculate BMI at http://apps.nccd.cdc.gov/dnpabmi.